The moon, named Chrysalis by researchers, may have broken apart 160 million years ago to create Saturn\u2019s rings<\/a>.<\/p>\n \u201cJust like a butterfly\u2019s chrysalis, this satellite was long-dormant and suddenly became active, and the rings emerged,\u201d says Jack Wisdom from MIT, who led the study.<\/p>\n The origin of Saturn\u2019s rings has been a long-standing question in planetary science.<\/p>\n Over the last decade, there has been mounting evidence that the rings are a lot younger than the planet and have potentially only existed for 100 million years or so.<\/p>\n The reason we can see them so well from Earth \u2013 in fact, Saturn\u2019s rings are the only planet\u2019s we can see through a telescope<\/a> \u2013 is because the planet is at a 26.7\u00b0 angle.<\/p>\n This tilt is thought to be due to a gravitational tug-of-war between Saturn and its neighbour Neptune<\/a>, called a resonance.<\/p>\n To be sure, however, requires knowing how Saturn\u2019s mass is distributed \u2013 something that the planet\u2019s rings make very difficult to measure.<\/p>\n It was only when NASA\u2019s Cassini spacecraft flew between the rings and the planet during its Grand Finale in 2017<\/a> that the measurement could be taken.\u00a0<\/span><\/p>\n With this in hand, researchers soon realised that Saturn was in reality just outside a resonance with Neptune \u2013 as if they had previously been in sync but were no longer.<\/p>\n Wisdom\u2019s team set out to find what could have pushed the two out of step, first suspecting one of Saturn\u2019s 83 moons.<\/p>\n Computer simulations showed this wasn\u2019t the case, but did reveal that removing a moon changed Saturn\u2019s tilt.<\/p>\n They then began investigating to see the effect of a lost moon, which was how they discovered Chrysalis.<\/p>\n Initially about the size of Iapetus, Saturn\u2019s current third-largest moon, Chrysalis would have become gravitationally unstable around 100 to 200 million years ago.<\/p>\n Once it strayed too close to Saturn, the planet\u2019s gravity<\/a> would rip the moon apart, creating icy debris that went on to form the rings.\u00a0 \u00a0<\/span><\/p>\n \u201cIt\u2019s a pretty good story, but like any other result it will have to be examined by others,\u201d says Wisdom.<\/p>\n \u201cBut it seems that this lost satellite was just a chrysalis waiting to have its instability.\u201d<\/p>\n![\"""\"](\""https:\/\/images.immediate.co.uk\/production\/volatile\/sites\/25\/2020\/07\/Cassini-Saturn-rings-115c2e7.jpg?quality=90&resize=620%2C320"\" "\\"\"\"\\"\/")
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